Dobkowolsky



(No' Model.) I

M. VON DOLIVO-DOBROWOLSKY.

GONTINUOUS ELECTRIC CURRENT DISTRIBUTING SYSTEM. No. 513,006. PatentedJan. 16, 1894.

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UNITED STATES PATENT OFFICE.

MICHAEL VON DOLIVO-DOBROXVOLSKY, OF BERLIN, GERMANY, ASSIGNOR TO THEALLGEMEINE ELEKTRIOITATS-GESELLSCHAET, OE SAME PLACE.

CONTINUOUS-ELECTRlC-CURRENT DISTRIBUTING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 513,006, dated January16, 1894.

Application filed November 24, 1893. Serial No. 91.908. (No model.)

To aZZ whom it may concern.-

Be it known that I, MICHAEL voN DOLIVO- DoBRowoLsKY, a subject of theEmperor of Russia, residing at Berlin, in the Kingdom of Prussia, GermanEmpire, have invented an Improved Continuous-Electric-OurrentDistributing System, of which the following is a specification.

This invention relates to the distribution [0 of continuous electriccurrent and more especially to the feedingwith such current of twoseries connected consumption circuits by the aid of the so called threewire system, and its object is to enable this system to be worked by themedium of but one current generating machine without sparking beingcaused at the point of connection between the neutral or compensatingwire and the dynamo machine.

It is a well known fact that electric current distributing systems canbe carried out with great saving of conducting material by employinghigh tension currents. \Vhere the consuming apparatus are bound-to apredeterminate maximum tension, the tension of the system can be causedto redouble or to treble or to increase to a still higher degree byuniting some of the consuming apparatus into groups and connecting thelatter in series.

Now the ordinary mode of establishing series connection of groups ofconsuming apparatus is very defective in rendering the groups dependenton each other. To prevent this use is frequently made of Hopkinsons so 35 called threeconductor system. In this system there are two seriesconnected groups of consuming apparatus, two series connected generatingmachines, two main conductors tor connecting the former with thelatter,and

a third conductor, called neutral or compensating conductor, which isbranched off from the point of connection of the two generating machinesand connects in series the two current consuming groups. The princi- 5pal disadvantage of the so combined system resides in the absolutenecessity of providing for at least two generating machines. Theattempts hitherto made to enable this three conductor system to beworked by the aid of but one current generating machine have beenwithout any practical result from the reason of the sparking caused onthe commutator by the third brush required to connect the compensatingconductor with the generating dynamo. Now I have discovered that thefeeding of two series connected consumption circuits of like tensionwith continuous current from but one generating machine can be arrivedat without the collector of the latter being subject to sparking byproperly applying the following principle: dividing the exceedingcurrent flowing back through the compensating wire into two partialcurrents and causing the latter to directly flow at diametrical oppositepoints into the armature winding of adynamo connected with the mains,the said dynamo consisting either in the generating dynamo itself or ina compensating machine, viz: a dynamo, receiving current from the mainsand running as an electro motor.

Based on this principle the present invention consists in connecting thecompensating conductor with the armature winding whether of thegenerating dynamo or a compensating dynamo by the medium of a selfinduction coil in such a manner that the center of the latter isconnected with the compensating conductor, while by its ends it isconnected with the armature winding at diametrically opposite points.Moreover, the said winding is given such a high self induction as isnecessary to prevent it from being traversed by alternating currentimpulsions while the resistance opposed by it to the pas- S5 sage of acontinuous current is but insignificant. By virtue of this organizationon the one hand the alternating current impulsions generated in thearmature winding are prevented from passing over into the compeno satingconductor by way of the induction coil, while on the other hand thecontinuous current flowing back through the said conductor is permittedto pass into the armature winding by the way of the induction coilwithout resistance, so that the feeding of the two series connectedcircuits continues without the tension of the latter being altered. Thesaid self induction coil may be so arranged as to rotate with thearmature of the ICC generating machine, or so as to be stationary, eachend forming a brush that is caused to slide on a ring shaped conductorfixed on the armature shaft and electrically connected rotate with thesame.

with one of two diametrically opposed points of the armature winding.

In order that the present invention may be fully understood I proceed todescribe the same in a more detailed manner reference being made to theannexed drawings forming part of this specification.

Figure 1 is a diagram of the improved three conductor system with theself induction coil rotating with the armature of the current generatingmachine, the latter being supposed to be a bipolar dynamo. Fig. 2 is adiagram of the improved three conductor system with the induction coilbeing stationary, the generating bipolar dynamo being represented inside elevation in order to show the arrangement of the brushes andcontact rings establishing permanent electrical connection betweendiametrically opposed points of the armature winding and the ends of theself induction coil. Fig. 3 is a diagram of a form of the improvedsystem inwhich the compensatin g conductor is connected through the selfinduction coil with the armature winding of a compensating machine, theself induction coil being stationary and connected with the armaturewinding in the same way asin Fig. 2.

Referring to Fig. 1 adenotes the ringshaped armature of the bipolargenerating dynamo A; a. the armature winding; N and S respectively thenorth and south poles of the field magnet,

and b, b the brushes feeding the mains m and m To simplify the drawingsthe coinmut-ator has been omitted, and the brushes are supposed to slidedirectly on the armature winding a.

i is the self induction coil. The coil 'i is arranged within thearmature and, moreover, it is attached to the armature shaft so as toThe ends 7." and i of coil 1' are respectively in electricalconnectionwith diametrically opposed points of armature winding a, as for instancewith the points a and a".

m is the neutral or compensating conductor connecting in series the twoconsuming circuits lettered o and '0 and containing for instance lampsrespectively Z and 1*. This neutral conductor is electrically connectedwith the center i of self induction coil '6. When the armature a iscaused to rotate, an

' alternating tension takes place at the points of connection, a and abut, as the construction of coil 2' is such as to give rise to a highdeg'rce'of self induction, thiscoil will not permit any appreciablequantity 'of alternating currents to flow through it. The center i ofcoil i-ha'sthe mean potential relatively to all the points of thearmature winding a; from this it results not only that the difierence oftension between 11' and 2' is equal to that between 2' and i but thatlikewise thedifierence of tension from brush 1) toward the point t isequalto that from brush b toward the said'point. As known theconnecting'coil team he made with a very high degree of self mature.

induction by coiling it on a closed body of iron e. As long as thenumber of working lamps respectively Z and Z is alike in each of thecircuits 0' and 12 the tension in the circuit o is equal to that in thecircuit 12 and there exists no current in the conductor 'm as it is inthe middle between the two tensions. But as soon as there are more lampsworking in one circuit than in the other, the consumption of current isgreater in the former than in the latter and the exceeding current willflow through the compensating conductor m in the direction of the arrow,'L. e toward the center 2' of the connecting COll/L. Arrived at thispoint the current splits up into two partial currents, one'of whichpasses toward and through the point a in the armature winding a, whilethe other passes toward and through the point a As'the returning currentis a continuous current the passage of the two partial currentsresulting from its splitting up in the point't' will not be resisted inany appreciable degree by the coil 41. Thus the tension of the two wiresconnected groups of consuming apparatus is maintained at the samedegree; whether there is a greater consumption of current in the one orthe other.group,the exceeding current is always allowed to flow backimmediately intotho armature'of the generatingmachine through theconductor m and the coil t. It is bythis means that the two seriesconnected groups of consuming apparatus are rendered perfectlyindependent on each other notwithstanding there is but one generatingmachine for feeding them with current.

In many cases it will not be possiblenor will it be advantageous in allinstances to place the connecting self induction coil within thearmature and so as to rotate with the same, sothat the said coil must bedisposed out of the generating machine. In such cases, the coil ispreferably arranged stationary and provision is made for'causinguninterrupted connection of its ends with diametrically opposed pointsof the rotating armature winding. Such an arrangement isdiagrammatically represented in Fig. 2.

As in Fig. 1 N and S'denote're'spectively the north and south poles ofthe field magnet of a bipolar generating dynamo A; a the ring shapedarmature of same being fixed on'the shaft 5; c the commutator to whichthe mains m and m are connected through the medium of the brushes b andb i the self induction coil for establishing electricalconnectionbetween the compensating conductor m and I two diametrically opposedpoints of the armature, and e the'closed body of iron-placed within coilc'.

sulated from each other. These r ingsa're connected by means of twowires, 2' and i with diametrically opposed points of the-ar- The end 2"of the'self induction coil t' is connected by a wire t to abrush i,-that rests'permanently on contact ring i and the On the shafts are fixedt'wo ring shaped contacts, i and 43", which are inother end 2' of coil1' is connected by a wire with a brush U, which is permanently restingon contact ring i Thus, when the armature is caused to rotate, thecontact rings i and i are forced to rotate with it and in doing so theyrub against the brushes i and f, whereby the permanency of electricalconnection between the ends of coils t' and the said two opposed pointsof the armature winding is maintained, and consequently the free returnof the exceeding current to the same allowed to take place at all times.

Fig. 3 illustrates diagrammatically a three conductor system in whichthe two series connected groups of consuming apparatus are fed withcurrent by one common generating machine, and in which the connectingselfinduction coil t' is made use of in combina' tion with a so calledcompensating machine, t'. e. a dynamo running as a motor and serving fortaking up the exceeding current. A denotes the generating bipolar dynamohaving the brushes 1) and b to which are connected the mains m and m 1;and are the two consuming circuits to be fed with current at liketension from the dynamo A, and m is the compensating conductor by whichthe circuits o and o are connected in series. 111 proximity of thelatter is arranged a bipolar dynamo A with ring shaped armature a thecoil a of which is connected with the mains through the collector 0*,the brushes I) and I) and the conductors m and an. e is the shaftcarrying the armature a and the collector 0*. t' denotes the selfinduction coil to the center 2' of which is connected the compensatingconductor m In this case the coil 2' is not brought into relation withthe armature winding of the generating dynamo A, but with the armaturewinding (t of the compensating machine A the arrangement being supposedto be made as described with reference to Fig. 2. That is to say, thecoil 4. provided with the closed iron body 6 is arranged out of thearmature and stationary, and its ends t" and t are connected by wires 2'and tiwith brushes 1' and 2' rubbing against ring shaped contact pieces2' and "i fixed on the armature shaft .9 and connected by wires t and 2'and the collector c with diametrically opposed points a and c of thearmature winding d. hen the system is working the dynamo A is fed withcurrent from the mains m and m through the conductors m and on, wherebyit is caused to rotate, the high self induction of coil 2' preventingthe current from passing through this coil. As long as there is a likenumber of consuming apparatus working on the circuits 'vand 0 there willalso be a like tension in both of them; consequently the middleconductor hi will receive no current and the dynamo A will work at thesame rate. But as soon as the number of working apparatus is changed inone or the other consuming circuit 1; or 22 the excess of current willbe led through the conductor 071 (see direction of arrow) toward thecenter i of coil i, where it splits up into two partial currents passinginto the armature winding a as described with reference to the winding aof the system represented in Fig. 1. It will readilybe seen that by thisarrangement the same effect as to the independency of the consumingcircuits on each other is obtained as in the system Fig. 1. Moreover, acertain saving of conducting material is obtained inasmuch as thecompensating conductor need not be continued to the generating dynamo.The arrangement represented in Fi 3 will therefore be the moreadvantageous the more the generating plant is distant from the seriesconnected consuming groups.

In the preceding description the generating machine has been supposed tobe a bipolar one, but this has only been done for the sake of simplicityof the drawings and it will readily be understood by any electricianthat the invention can also be made use of in combination withmultipolar machine and with armature windings of any description.Moreover, the invention is not limited to the use of but one generatingmachine, but it may also be combined with several generating machinesconnected in parallel, which arrangement is a well known equivalent forone generating machine.

I am aware that attempts have been made to feed with current threeconductor systems by the aid of one common generating machine, and I donot claim the use of such a common generating machine in combinationwith two series connected groups of current consuming apparatus, but

WVhat I claim as my invention is- 1. In a system for distributingelectricity to two series connected groups of consuming apparatus by theaid of two main conductors and a compensating conductor the combinationwith the compensating conductor and a continuous current-dynamoconnected with the mains of a coil of high self-induction connected atboth ends with diametrically opposed points of the armature winding ofsaid dynamo, and in its center with the said compensating conductor, asand for the purpose stated.

2. In a system for distributing electricity the combination with twoseries connected groups of current consuming apparatus, two mainconductors, a compensating conductor and one continuous currentgenerating machine or its described equivalent, of a coil of high selfinduction connected at both ends with diametrically opposed points ofthe armature winding of the generating machine and connected in itscenter with the said compensating conductor, as and for the purposestated.

3. In a system for distributing electricity the combination with twoseries connected groups of current consuming apparatus, two mainconductors, a compensating conductor, a continuous current generatingmachine, and a compensating machine running as an electronotor, of acoil of high selfinduetion connected at both ends with diametricallyopposed points of the armature winding of said compensating machine andconnected in its center with the said compensating conductor, as and forthe purpose stated.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

MICHAEL VON "DOLIVO-DOBROWOLSKY. Witnessesz' SOHMOLLER, A. WEBER,

Ingenieurs, Berlin.

